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Question about process safety and distributed safety

Created by: PCI at: 11/19/2010 10:21 AM (5 Replies)

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11/19/2010 10:21 AM	Rate (0)
PCI Posts: 2 Rating: (0)	i come acrros a thread in this forum saying that for satety system, we can have 1)distributed safety 2)F CPU 3)FH CPU right now, for my system, i have a S7-400H cpu with a fail safe license in it, then for remote racks, i have normal IO and safety IO where you can distinguish by looking at the yellow lable. So system like this fall into which category listed above. People in my company told me this is called process safety but this is not belong to any of the category listed above. Another question is i saw from siemens catalog, there is one type of CPU called S7-416F which is already a safety CPU, so what is the difference between S7-416F and the (S7-400H with fail safe license). thanks..
PCI Posts: 2 Rating: (0)
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11/19/2010 1:36 PM	Rate (0)
OmegaProjects Silver Member Joined: 11/14/2008 Last visit: 5/6/2024 Posts: 504 Rating: (22)	Difference between F and H is that , F is more for safety applications and H for more fault-tolerant systems... Also see pdf pls... Attachment S7_400_h_en_en-US.zip (371 Downloads)

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11/22/2010 3:14 PM	Rate (1)
dmertens Bronze Member Joined: 10/3/2007 Last visit: 6/25/2024 Posts: 188 Rating: (34)	Siemens has two fails safe product lines both based on S7 hardware. This is extremely confusing and can cause a lot of problems if you do not know the difference and the which hardware is compatible with which software. The two produc lines are : 1: Distributed safety. This is aimed at machine safety, it was developed on S7-300F hardware originally but for performance reasons a S7-416F was added later. As this software was aimed at the machine automation markets it has several features which may be a show stopper when used in process plants or machines that have a high availability requirement. The safety program is created in Step 7 FUP or LAD and does not allow any changes in runtime. There are no redundant CPU's available for distributed safety. There are no advanced libraries or software tools available (e.g. safety matrix) 2: Fail safe systems : This is aimed at the process industry and can only be used on S7-414H and S7-417H CPU's (both in a redundant and non redundant configuration). The software is developed using CFC. Advanced libraries for burner management and typical safety functions are available and advanced softaware developement tools like safety matrix can make the ESD programming a lot easier andallow easy integration inWinCC/PCS7 operator interface. Before starting a project in either of these environments, make sure you have the proper qualification and read the relevant manuals as these projects are usually mandatory safety measures and subject to external approvals (TUV) and you may face severe legal problems if something goes wrong with a machine's or plant's safety interlocking. The consequences can be catastrophic.

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This contribution was helpful to 2 thankful Users H-H hamhead

11/22/2010 8:00 PM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Hello PCI, PCI right now, for my system, i have a S7-400H cpu with a fail safe license in it, then for remote racks, i have normal IO and safety IO where you can distinguish by looking at the yellow lable. So system like this fall into which category listed above. It falls in the FH category. PCI People in my company told me this is called process safety but this is not belong to any of the category listed above. I give your colleagues all the respect but one of the 1st things I've learntwhen I was starting my career is to trust what I readand respect whatI hear. The term Process Safety is good no doubt however the name that's used by all technology providers and engineering houses is SIS (Safetyinstrumented system). The name SIS is used to describe any ESD (Emergency shut down) or PSD (Process shut down) system. In Siemens world as you could see we have the F/FH categories which is as stated by dmertensis mainly used to cover SIS applications. I think you will find thislink very useful. It has 2 main links, one for distributed safety (Factory automation) and the other isSafety Integrated for the Process Automation in which you can read and learn many things. Normally,an SISis controlled by a special PLC that has nothing to do with process control (PID loops). The main task of this PLC is to handle the safety logic of the plant. This fail safe PLC communicates with process controller (DCS) through a gateway. It's alwayslittle hard to find both DCS and ESD systems coming from a single vendor and even if you can get them from a single technology provider, it's still hard for both to share the same engineering tools. Now SIEMENS put both the fail safe PLC (F or FH) and the process controller (S7-400 or 400H) under the PCS7 which means simplified engineering and easy integration. Moreover, both process control and SIS can be integrated ina single controller which is your case since you have standard and fail safe modules combined together. This is well shown in Integrated Control + Safety. So, based on this link we can create a new category for your system and call it common FH . PCI Another question is i saw from siemens catalog, there is one type of CPU called S7-416F which is already a safety CPU, so what is the difference between S7-416F and the (S7-400H with fail safe license). That's a tough question to answer. This might not be the perfect answer and just represents my own opinion. 1st of all the most important thing for a fail safe system is the certificate. And the important thing in the certificate is which standards have been taken into consideration while issuing the certificate. Both distributed safety and F-systems are mainly based on IEC61508. Then distributed safety which is more related to safety of machinery (Factory automation) is more based on IEC62061. The F-system which is more related to process safety is more based on IEC61511. There are 2 certificates now, one for distributed safety (check report)and the other is the F/FH certificate (check report). You can find that both had taken into consideration the IEC61511. The 416F has been mentioned in thereport of the distributed safety (Machinery) and was not mentioned in the S7-F/FH (Process) report which means it's not tested with the S7-F library blocks. For example, you can't use safety matrix with 416F because 1st Siemens doesn't support it and 2nd this solution will not be TUV certified. You can also check the area of application of S7-400 fail safe CPUs here where you will not find the word process mentioned I hope I answered your question. Best regards, H-H
	Last edited by: H-H at: 11/23/2010 12:29 AM Last edited by: H-H at: 11/23/2010 12:20 AM
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This contribution was helpful to 2 thankful Users fritz hamhead

11/23/2010 12:39 AM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Dear dmertens, I really like what you have written. I just have some comments. dmertens 2: Fail safe systems : This is aimed at the process industry and can only be used on S7-414H and S7-417H CPU's (both in a redundant and non redundant configuration) I don't know why Siemens didn't put the latest reportof certificate inthispage. Anyhow, the latest report can be found here in which you can see that the 412-3H has been included to give it the title F so it becomes 412-3FH. dmertens 2: Fail safe systems : This is aimed at the process industry and can only be used on S7-414H and S7-417H CPU's (both in a redundant and non redundant configuration). The software is developed using CFC. Advanced libraries for burner management and typical safety functions are available It's little bit confusing but the burner management system blocks can be used in both distributed safety and S7-F library. Where can you find an overview of the "Fuel Technology" function blocks for fail-safe automation systems? Best regards, H-H

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11/23/2010 8:13 AM	Rate (0)
PCI Posts: 2 Rating: (0)	Thanks you all, information here should be enough for me to fully understand what it means.
PCI Posts: 2 Rating: (0)
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